"I'm no greater or lesser than anyone facing death. That's the only lesson that keeps you from being a true Zen Master. Death is a part of life. A transition, a rebirth, something that your young friends here have learned recently."

The Zen Master trained Yen Lo for twenty years, though when the time came to choose a replacement, he chose his daughter An Ling over Yen Lo. He made this decision because An Ling was a better pupil and Yen Lo used his abilities for evil, though Yen Lo felt betrayed and swore revenge.

In late 2001, Yen Lo attempted to kill the Zen Master, though An Ling defended him and he retreated. Knowing that only the Dragon Blade could stop Yen Lo, the Zen Master sent An Ling to retrieve it. As she returned with the blade, Yen Lo appeared and fatally stabbed his former master before taking him through a portal.

In Limbo, the Zen master tried to convince Yen Lo to redeem himself and reincarnate. Yen Lo refused and told his former master of his plan, to trap all Zen Masters in Limbo so they could never reincarnate and all their magic and knowledge would be lost. When the Zen Master asked how Yen Lo could escape Limbo without water, Yen Lo replied that there was water in the clouds above.

Piper trading places with the Zen Master.

Yen Lo left Limbo in order to kill An Ling, though he failed and escaped with the Dragon Blade when the Charmed Ones intervened. Inspired by the accidental body swap between Paige and Phoebe, Piper used the same potion to switch bodies with the Zen Master. Yen Lo instantly figured out something was wrong and captured Piper's soul with the blade.

At the manor, Zen Master learned that Yen Lo had captured Piper's soul by observing him through a portal. When they all arrived in Limbo to save her, Phoebe engaged Yen Lo in a fight while Paige freed Piper. She then orbed the blade to Phoebe, who used it to capture Yen Lo's soul. With him gone, Limbo was no longer corrupted by his fears and returned to a peaceful place.

An Ling wanted to return to the manor so Leo could heal her father, though the Zen Master told her that he was mortally wounded and that it was his time. He told An Ling was death and rebirth were a natural part of life, which was the final lesson she needed to learn before becoming a Zen Master herself. He then said goodbye to his daughter and took Yen Lo's soul with him to be reincarnated.